Cutting tool

Abstract

A cutting tool, comprising a substrate and a coating disposed on the substrate, wherein the coating comprises a first layer, the first layer consists of an alternate layer in which a first unit layer and a second unit layer are alternately stacked, the first unit layer is composed of Al a Ti (1-a-b) Si b N, the second unit layer is composed of Al c Cr (1-c-d) Cu d N, the a, the b, the c, and the d satisfy 0.50≤a≤0.75, 0.005≤b≤0.20, 0.50≤c≤0.85, and 0.005≤d<0.10, an average thickness of the first unit layer is 2 nm or more and 50 nm or less, and an average thickness of the second unit layer is 2 nm or more and 50 nm or less.

The invention claimed is: 
     
       1. A cutting tool, comprising a substrate and a coating disposed on the substrate,
 wherein the coating comprises a first layer, 
 the first layer consists of an alternate layer in which a first unit layer and a second unit layer are alternately stacked, 
 the first unit layer is composed of Al a Ti (1-a-b) Si b N, 
 the second unit layer is composed of Al c Cr (1-c-d) Cu d N, 
 the a, the b, the c, and the d satisfy
 0.50≤a≤0.75, 
 0.005≤b≤0.20, 
 0.50≤c≤0.85, and 
 0.005≤d<0.10, 
 
 an average thickness of the first unit layer is 2 nm or more and 50 nm or less, and 
 an average thickness of the second unit layer is 2 nm or more and 50 nm or less. 
 
     
     
       2. The cutting tool according to  claim 1 , the b and the d satisfy a relationship: b/d≥1. 
     
     
       3. The cutting tool according to  claim 1 , wherein in the first unit layer and the second unit layer adjacent to the first unit layer, a ratio λ1/λ2 of thickness of the first unit layer λ1 to thickness of the second unit layer λ2, is more than 1.0. 
     
     
       4. The cutting tool according to  claim 1 , wherein the first layer has a thickness of 0.5 μm or more and 10 μm or less. 
     
     
       5. The cutting tool according to  claim 1 , wherein the coating further comprises a second layer disposed between the substrate and the first layer, and
 the second layer is composed of a first compound 
 consisting of at least one element selected from a first group consisting of Group 4, 5, and 6 elements in the periodic table, aluminum, and silicon or 
 consisting of at least one element selected from the first group and at least one element selected from a second group consisting of carbon, nitrogen, oxygen, and boron. 
 
     
     
       6. The cutting tool according to  claim 1 , wherein the coating further comprises a third layer disposed on the opposite side of the first layer to the substrate, and
 the third layer is composed of a second compound 
 consisting of at least one element selected from the first group consisting of Group 4, 5, and 6 elements in the periodic table, aluminum, and silicon or 
 consisting of at least one element selected from the first group and at least one element selected from the second group consisting of carbon, nitrogen, oxygen, and boron. 
 
     
     
       7. The cutting tool according to  claim 1 , wherein the coating has a thickness of 0.5 μm or more and 12 μm or less. 
     
     
       8. The cutting tool according to  claim 1 , wherein the substrate comprises a cemented carbide, a cermet, cubic boron nitride sintered material, diamond sintered material, high-speed steel, or a ceramic.